Centrica PLC — Capital/Financing Update 2012

Apr 2, 2012

SUPPLEMENT DATED 2 APRIL, 2012 TO THE BASE PROSPECTUS DATED 27 SEPTEMBER,

2011

CENTRICA plc

(incorporated in England and Wales with limited liability under registered number 3033654)

U.S.\$8,000,000,000 Euro Medium Term Note Programme

This Supplement (the Supplement) to the Base Prospectus dated 27 September, 2011, as supplemented by the supplement dated 2 December, 2011 and the supplement dated 23 February, 2012 (the Base Prospectus), which comprises a base prospectus, constitutes a supplementary prospectus for the purposes of Section 87G of the Financial Services and Markets Act 2000 (the FSMA) and is prepared in connection with the Euro Medium Term Note Programme (the Programme) established by Centrica plc (the Issuer). Terms defined in the Base Prospectus have the same meaning when used in this Supplement.

This Supplement is supplemental to, and should be read in conjunction with, the Base Prospectus and any other supplements to the Base Prospectus issued by the Issuer.

The Issuer accepts responsibility for the information contained in this Supplement. To the best of the knowledge of the Issuer (which has taken all reasonable care to ensure that such is the case) the information contained in this Supplement is in accordance with the facts and does not omit anything likely to affect the import of such information.

This Supplement is prepared for the purpose of updating the Base Prospectus, as described below.

On 30 March, 2012, the Issuer published its annual report and accounts for the year ended 31 December, 2011 (the Annual Report).

A copy of the Annual Report has been filed with the Financial Services Authority and, by virtue of this Supplement, the auditor's report and audited consolidated and non-consolidated annual financial statements for the financial year ended 31 December, 2011 which appear on pages 64 to 128 of the Annual Report (excluding the section entitled "Pro forma information" on page 106 thereof) are incorporated in, and form part of, the Base Prospectus.

The credit ratings of the Group referred to on page 84 of the Annual Report have been assigned by Moody's Investors Service Ltd (Moody's) and Standard & Poor's Credit Market Services Europe Limited (S&P). Each of Moody's and S&P is established in the European Union and is registered under Regulation (EC) No. 1060/2009. As such, Moody's and S&P are included in the list of credit rating agencies published by the European Securities and Markets Authority on its website in accordance with such Regulation.

Copies of all documents incorporated by reference in the Base Prospectus can be obtained from the registered office of the Issuer and from the specified office of the Paying Agent for the time being in London.

If documents which are incorporated by reference themselves incorporate any information or other documents therein, either expressly or implicitly, such information or other documents will not form part of this Supplement for the purposes of the Prospectus Directive (Directive 2003/71/EC) except where such information or other documents are specifically incorporated by reference or attached to this Supplement. To the extent that there is any inconsistency between (a) any statement in this Supplement or any statement incorporated by reference into the Base Prospectus by this Supplement and (b) any other statement in or incorporated by reference in the Base Prospectus, the statements in (a) above will prevail.

Any non-incorporated parts of a document referred to herein are either deemed not relevant for an investor or are otherwise covered elsewhere in the Base Prospectus.

Save as disclosed in this Supplement, the supplement dated 2 December, 2011 and the supplement dated 23 February, 2012, there has been no other significant new factor, material mistake or inaccuracy relating to information included in the Base Prospectus since the publication of the Base Prospectus.

Investors should be aware of their rights under section 87Q(4) of FSMA.